78 On the Vegetation of the Carboniferous Period. 



from New Zealand to the Society and Sandwich Islands. Take, on 

 the other hand, the campos of Brazil, the sandy flats of Southern 

 Africa, and the somewhat similar plains of Australia, and, steril 

 though they appear at first sight, they will be found to abound in 

 many kinds of flowering plants ; but unaccompanied with ferns. 



This prevalence of ferns has been long adduced in proof of the 

 climate of the carboniferous period being temperate, equable, and 

 humid ; and so it, no doubt, was ; but I am not aware that it has 

 been hitherto regarded as probable evidence of the paucity of other 

 plants, and the general poverty of the whole flora which character- 

 ised that formation. If, however, the laws of existing vegetation are 

 to be considered as having had equal force at that time when the 

 fossil one flourished, we must conclude that the predominance of ferns 

 in general, and of certain species of Pecopteris (a fern apparently 

 allied to our Pteris), over a great area, together with the remarkable 

 similarity of the English fossils with those of North America, are 

 all indications that the flora of that period was poor in a number of 

 species. 



Let it not be supposed that this prevalence of an order, which, in 

 point of complexity of structure, is low in the system of plants, is a 

 fact favourable to the hypothesis that the vegetation of which it ap- 

 pears to form a large part, was less highly developed than what suc- 

 ceeded it. We know too little of the structure of the ferns of that day, 

 to pronounce them either more or less complete than their allies of 

 the present time ; while of L^copodiacecB* it may be safely as- 

 serted, that they were of a form and stature far more noble, and 

 in structure more complicated, than any plants of that order now 

 existing. (^Vide vol. ii.. Part 2, of Memoirs of the Geological Sur- 

 vey/ of Great Britain.) 



On Dolomisation. By A. VoN MORLOT. 



A. Von Morlot states that the metamorphic nature of dolo- 

 mite was first suggested by Arduino-t As early as 1827 

 W. Haidinger, in an article on pseudomorphism, described 

 certain dolomitic pseudomorpbs, and states that in their for- 

 mation " part of the carbonate of lime was replaced by the 

 carbonate of magnesia, so as to form in the new species a com- 



* See " Essay on the Structure and Affinities of Lepidostrobus," in the pre- 

 sent volume of Survey Reports. 



t Osservazioni chimiche sopra alcuni Fossili. Venezia, 1779. 



